+x-+--+
+ | | |
x\x +--+x-+
| + \
1 +x-+
Thrull x
+
|
+
|
+x-+
\
+x-+
x
+--+
| |
+--+
x |
+ +
\
+x-+
1 = Thrull {1-50}
Here is the universal key.